Atomically flat aluminum-oxide barrier layers constituting magnetic tunnel junctions observed by in situ scanning tunneling microscopy

2005 ◽  
Vol 87 (17) ◽  
pp. 171909 ◽  
Author(s):  
M. Mizuguchi ◽  
Y. Suzuki ◽  
T. Nagahama ◽  
S. Yuasa
Keyword(s):  
Aluminum Oxide ◽  
Scanning Tunneling Microscopy ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Barrier Layers ◽  
Oxide Barrier ◽  
Atomically Flat

Surface Morphology of Epitaxial Magnetic Tunnel Junctions

2007 ◽  
Vol 7 (1) ◽  
pp. 255-258
Author(s):  
M. Mizuguchi ◽  
Y. Suzuki ◽  
T. Nagahama ◽  
S. Yuasa
Keyword(s):  
Surface Morphology ◽  
Flat Surface ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Magnetoresistance ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Magnetoresistance Ratio

The surface morphology of epitaxial Fe(001)/MgO(001)/Fe(001) magnetic tunnel junctions, which show the giant tunneling magnetoresistance effect, was investigated by in situ scanning tunneling microscopy. It was observed that an epitaxial MgO barrier layer forms flat surface structures. The surface was flatter with distinct steps and terraces after annealing, which would lead to an increase of the tunneling magnetoresistance ratio. Examination of the local electronic structures of 1.05-nm-thick MgO barrier layers by scanning tunneling spectroscopy revealed no pinholes in the layers, so they would be perfect barriers in magnetic tunnel junctions.

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